Problem with Image file

Question

Hi,
Iam facing with one problem.I have one swing interface through which I can upload files(back end servlet programme).Now I can upload all types of file but problem with image file it uploading perfectly that means size of the uploaded file is ok but its format damaged.It can not be open.My backend servlet programme is ok coz i tested it with html form it is working perfectly.Problem with swing interface.Plz guide me where I done a mistake.Below r my codes:-
ImageIcon Upload=new ImageIcon("images/Upload.gif");
     Button=new JButton(Upload);
     Button.setToolTipText("Upload");
Button.addActionListener(new ActionListener()
public void actionPerformed(ActionEvent e)
          int returnVal = fc.showOpenDialog(ActionDemo4.this);
          if (returnVal == JFileChooser.APPROVE_OPTION) {
          File file = fc.getSelectedFile();
String aa=file.getAbsolutePath();
          textArea3.append(aa);
               textArea2.append("Local URL:");
long l=file.length();
          try
          byte buff[]=new byte[(int)file.length()];
          InputStream fileIn=new FileInputStream(aa);
          int i=fileIn.read(buff);
          String conffile=new String(buff);
          String str1=textArea10.getText();
url = new URL ("http://127.0.0.1:7001/servletUpload?x="+str1);
     urlConn = url.openConnection();
     urlConn.setDoInput (true);
     urlConn.setDoOutput (true);
     urlConn.setUseCaches (false);
     urlConn.setRequestProperty("Content-Type","multipart/form-data;boundry=-----------------------------7d11e410e500f2");
     printout = new DataOutputStream (urlConn.getOutputStream ());
String content ="-----------------------------7d11e410e500f2\r\n"+"Content-Disposition: form-data;"+"name=\"upload\"; filename=\""+aa+"\"\r\n"+"Content-Type: application/octet-strem\r\n\r\n\r\n"+conffile+"-----------------------------7d11e410e500f2--\r\n";
printout.writeBytes(content);
printout.flush ();
printout.close ();
Best Regards
Bikash

Answer 1

The errors are here:
          byte buff[]=new byte[(int)file.length()];
          InputStream fileIn=new FileInputStream(aa);
          int i=fileIn.read(buff);
          String conffile=new String(buff); (conffile is a String object containing the image)
and here:
String content ="-----------------------------7d11e410e500f2\r\n"+"Con
ent-Disposition: form-data;"+"name=\"upload\";
filename=\""+aa+"\"\r\n"+"Content-Type:
application/octet-strem\r\n\r\n\r\n"+conffile+"--------
--------------------7d11e410e500f2--\r\n";
printout.writeBytes(content);conffie is sent to the server but
it's non possible to treat binary data as String!
Image files must be sent as byte[] NOT as String ......